Split-beam echosounders provide estimation of fish size by directly measuring their
target strength. A model that can be used to evaluate and optimize split-beam sonar
performance is presented. The model has been used to generate beam patterns to
match prototype instruments and to simulate acoustic signals based on the scattering
of sound from particles in a three-dimensional domain. The sum of the contribution
of the scatterers is sampled at the transducer locations, resulting in simulated signals
used for data processing and sonar performance prediction. The model’s capabilities
were evaluated through comparisons with ASL Environmental Sciences’ AZFP-Split
prototype system. The field trials were conducted in Saanichton, BC, by lowering
a calibration target sphere to a range of 220 m in the acoustic beam. Both model
prediction and prototype system performance show accuracy of σ = 0.2 dB at 25 m
range. Potential future applications of the model include exploring methods of target
separation and improving accuracy when presented with complex target structures
